Polyester resin, as the term is used, designates a linear-type alkyd possessing unsaturation in the polymer chain. These unsaturated polyesters may be crosslinked by reaction with monomers such as styrene, acrylates or diallyl-phthalate usually in the presence of a peroxide to form insoluble and infusible resins without the formation of a by-product during the curing reaction. Polyester resins possess broad commercial utility due to their versatility and cost effectiveness. As a result of the increased applications, it has become essential to increase the cure rates of such polyester resins at low temperatures without detracting from the physical properties of the resins.
Although previous technology has used acetyl acetone peroxide to effect a rapid room temperature cure of polyester resins, the full cure of the part has suffered resulting in residual styrene contents which are no better and often worse than the routine methyl ethyl ketone peroxide (MEKP) cured systems.
Thus, there is a need for more effective initiators and cure promoters which will provide a fast cure without adversely affecting the physical properties of the cured resins.